Editing C file input/output (section)

===Functions===
Most of the C file input/output functions are defined in {{mono|<stdio.h>}} (or in the [[C++]] header {{mono|cstdio}}, which contains the standard C functionality but in the {{mono|std}} [[namespace]]).

{| class="wikitable"
|-
!
! Byte<br />character
! Wide<br />character
! Description
|-
! rowspan=9 | File access
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|fopen}}[https://en.cppreference.com/w/c/io/fopen fopen]
| Opens a file (with a non-Unicode filename on Windows and possible UTF-8 filename on Linux)
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|popen}}[https://man7.org/linux/man-pages/man3/popen.3.html popen]
| opens a process by creating a pipe, forking, and invoking the shell
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|freopen}}[https://en.cppreference.com/w/c/io/freopen freopen]
| Opens a different file with an existing stream
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|fflush}}[https://en.cppreference.com/w/c/io/fflush fflush]
| Synchronizes an output stream with the actual file
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|fclose}}[https://en.cppreference.com/w/c/io/fclose fclose]
| Closes a file
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|pclose}}[https://man7.org/linux/man-pages/man3/pclose.3p.html pclose]
| closes a stream
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|setbuf}}[https://en.cppreference.com/w/c/io/setbuf setbuf]
| Sets the buffer for a file stream
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|setvbuf}}[https://en.cppreference.com/w/c/io/setvbuf setvbuf]
| Sets the buffer and its size for a file stream
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|fwide}}[https://en.cppreference.com/w/c/io/fwide fwide]
| Switches a file stream between wide-character I/O and narrow-character I/O
|-
! rowspan=2 | Direct <br /> input/output
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|fread}}[https://en.cppreference.com/w/c/io/fread fread]
| Reads from a file
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|fwrite}}[https://en.cppreference.com/w/c/io/fwrite fwrite]
| Writes to a file
|-
! rowspan=9 | Unformatted <br /> input/output
| style="font-family:monospace" | {{anchor|fgetc|getc}}[https://en.cppreference.com/w/c/io/fgetc fgetc]<br />[https://en.cppreference.com/w/c/io/getc getc]
| style="font-family:monospace"| {{anchor|fgetwc|getwc}}[https://en.cppreference.com/w/c/io/fgetwc fgetwc]<br />[https://en.cppreference.com/w/c/io/getwc getwc]
| Reads a byte/{{mono|wchar_t}} from a file stream
|-
| style="font-family:monospace" | {{anchor|fgets}}[https://en.cppreference.com/w/c/io/fgets fgets]
| style="font-family:monospace" | {{anchor|fgetws}}[https://en.cppreference.com/w/c/io/fgetws fgetws]
| Reads a byte/{{mono|wchar_t}} line from a file stream
|-
| style="font-family:monospace" | {{anchor|fputc|putc}}[https://en.cppreference.com/w/c/io/fputc fputc]<br />[https://en.cppreference.com/w/c/io/putc putc]
| style="font-family:monospace" | {{anchor|fputwc|putwc}}[https://en.cppreference.com/w/c/io/fputwc fputwc]<br />[https://en.cppreference.com/w/c/io/putwc putwc]
| Writes a byte/{{mono|wchar_t}} to a file stream
|-
| style="font-family:monospace" | {{anchor|fputs}}[https://en.cppreference.com/w/c/io/fputs fputs]
| style="font-family:monospace" | {{anchor|fputws}}[https://en.cppreference.com/w/c/io/fputws fputws]
| Writes a byte/{{mono|wchar_t}} string to a file stream
|-
| style="font-family:monospace" | {{anchor|getchar}}[https://en.cppreference.com/w/c/io/getchar getchar]
| style="font-family:monospace" | {{anchor|getwchar}}[https://en.cppreference.com/w/c/io/getwchar getwchar]
| Reads a byte/{{mono|wchar_t}} from stdin
|-
| style="font-family:monospace" | {{anchor|gets}}<s>[https://en.cppreference.com/w/c/io/gets gets]</s>
| {{n/a}}
| Reads a byte string from stdin until a newline or end of file is encountered (deprecated in C99, removed from C11)
|-
| style="font-family:monospace" | {{anchor|putchar}}[https://en.cppreference.com/w/c/io/putchar putchar]
| style="font-family:monospace" | {{anchor|putwchar}}[https://en.cppreference.com/w/c/io/putwchar putwchar]
| Writes a byte/{{mono|wchar_t}} to stdout
|-
| style="font-family:monospace" | {{anchor|puts}}[https://en.cppreference.com/w/c/io/puts puts]
| {{n/a}}
| Writes a byte string to stdout
|-
| style="font-family:monospace" | {{anchor|ungetc}}[https://en.cppreference.com/w/c/io/ungetc ungetc]
| style="font-family:monospace" | {{anchor|ungetwc}}[https://en.cppreference.com/w/c/io/ungetwc ungetwc]
| Puts a byte/{{mono|wchar_t}} back into a file stream
|-
! rowspan=5 | Formatted <br /> input/output
| style="font-family:monospace" | {{anchor|scanf|fscanf|sscanf}}[https://en.cppreference.com/w/c/io/scanf scanf]<br />[https://en.cppreference.com/w/c/io/fscanf fscanf]<br />[https://en.cppreference.com/w/c/io/sscanf sscanf]
| style="font-family:monospace" | {{anchor|wscanf|fwscanf|swscanf}}[https://en.cppreference.com/w/c/io/wscanf wscanf]<br />[https://en.cppreference.com/w/c/io/fwscanf fwscanf]<br />[https://en.cppreference.com/w/c/io/swscanf swscanf]
| Reads formatted byte/{{mono|wchar_t}} input from stdin,<br />a file stream or a buffer
|-
| style="font-family:monospace" | {{anchor|vscanf|vfscanf|vsscanf}}[https://en.cppreference.com/w/c/io/vscanf vscanf]<br />[https://en.cppreference.com/w/c/io/vfscanf vfscanf]<br />[https://en.cppreference.com/w/c/io/vsscanf vsscanf]
| style="font-family:monospace" | {{anchor|vwscanf|vfwscanf|vswscanf}}[https://en.cppreference.com/w/c/io/vwscanf vwscanf]<br />[https://en.cppreference.com/w/c/io/vfwscanf vfwscanf]<br />[https://en.cppreference.com/w/c/io/vswscanf vswscanf]
| Reads formatted input byte/{{mono|wchar_t}} from stdin,<br />a file stream or a buffer using variable argument list
|-
| style="font-family:monospace" | {{anchor|printf|fprintf|sprintf|snprintf}}[https://en.cppreference.com/w/c/io/printf printf]<br />[https://en.cppreference.com/w/c/io/fprintf fprintf]<br />[https://en.cppreference.com/w/c/io/sprintf sprintf]<br />[https://en.cppreference.com/w/c/io/snprintf snprintf]
| style="font-family:monospace" | {{anchor|wprintf|fwprintf|swprintf}}[https://en.cppreference.com/w/c/io/wprintf wprintf]<br />[https://en.cppreference.com/w/c/io/fwprintf fwprintf]<br />[https://en.cppreference.com/w/c/io/swprintf swprintf]
| Prints formatted byte/{{mono|wchar_t}} output to stdout,<br />a file stream or a buffer
|-
| style="font-family:monospace" | {{anchor|vprintf|vfprintf|vsprintf|vsnprintf}}[https://en.cppreference.com/w/c/io/vprintf vprintf]<br />[https://en.cppreference.com/w/c/io/vfprintf vfprintf]<br />[https://en.cppreference.com/w/c/io/vsprintf vsprintf]<br />[https://en.cppreference.com/w/c/io/vsnprintf vsnprintf]
| style="font-family:monospace" | {{anchor|vwprintf|vfwprintf|vswprintf}}[https://en.cppreference.com/w/c/io/vwprintf vwprintf]<br />[https://en.cppreference.com/w/c/io/vfwprintf vfwprintf]<br />[https://en.cppreference.com/w/c/io/vfwprintf vswprintf]
| Prints formatted byte/{{mono|wchar_t}} output to stdout,<br />a file stream, or a buffer using variable argument list
|-
| style="font-family:monospace" | {{anchor|perror}}[https://en.cppreference.com/w/c/io/perror perror]
| {{n/a}}
| Writes a description of the [[errno.h|current error]] to stderr
|-
! rowspan=5 | File positioning
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|ftell}}[https://en.cppreference.com/w/c/io/ftell ftell]<br/>ftello
| Returns the current file position indicator
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|fseek}}[https://en.cppreference.com/w/c/io/fseek fseek]<br/>fseeko
| Moves the file position indicator to a specific location in a file
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|fgetpos}}[https://en.cppreference.com/w/c/io/fgetpos fgetpos]
| Gets the file position indicator
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|fsetpos}}[https://en.cppreference.com/w/c/io/fsetpos fsetpos]
| Moves the file position indicator to a specific location in a file
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|rewind}}[https://en.cppreference.com/w/c/io/rewind rewind]
| Moves the file position indicator to the beginning in a file
|-
! rowspan=3 | Error<br />handling
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|clearerr}}[https://en.cppreference.com/w/c/io/clearerr clearerr]
| Clears errors
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|feof}}[https://en.cppreference.com/w/c/io/feof feof]
| Checks for the end-of-file
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|ferror}}[https://en.cppreference.com/w/c/io/ferror ferror]
| Checks for a file error
|-
! rowspan=4 | Operations <br />on files
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|remove}}[https://en.cppreference.com/w/c/io/remove remove]
| Erases a file
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|rename}}[https://en.cppreference.com/w/c/io/rename rename]
| [[rename (computing)|Rename]]s a file
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|tmpfile}}[https://en.cppreference.com/w/c/io/tmpfile tmpfile]
| Returns a pointer to a temporary file
|-
| colspan=2 style="text-align:center;font-family:monospace" | {{anchor|tmpnam}}[https://en.cppreference.com/w/c/io/tmpnam tmpnam]
| Returns a unique filename
|}